docs: def _check_guts_toc_mtime(attr, old, toc, last_build, pyc=0):
      """
      rebuild is required if mtimes of files listed in old toc are newer
      than ast_build
  
      if pyc=1, check for .py files, too
      """
      for (nm, fnm, typ) in old:
          if mtime(fnm) > last_build:
              logger.info("building because %s changed", fnm)
              return True
          elif pyc and mtime(fnm[:-1]) > last_build:
              logger.info("building because %s changed", fnm[:-1])
              return True
      return False